Welcome to the 2014 Embryology Course!
- Each week the individual assessment questions will be displayed in the practical class pages and also added here.
- Copy the assessment items to your own page and provide your answer.
- Note - Some guest assessments may require completion of a worksheet that will be handed in in class with your student name and ID.
|Individual Lab Assessment|
|Lab 12 - Stem Cell Presentation Assessment||More Info|
Belbin Model Team Roles
Although I feel as if aspects of my personality and demeanour may fall into more than one specific category, the Monitor Evaluator may be the role that best describes my contribution to group work tasks :)
Monitor Evaluators are fair and logical observers and judges of what is going on in the team. Since they are good at detaching themselves from bias, they are often the ones to see all available options with the greatest clarity and impartiality. They take a broad view when problem-solving, and by moving slowly and analytically, will almost always come to the right decision. However, they can become very critical, damping enthusiasm for anything without logical grounds, and they have a hard time inspiring themselves or others to be passionate about their work.
Lab 1: Fertilisation Reference
The usefulness of low O2 concentrations in human IVF technology is an ongoing question with numerous laboratories still uncertain as to the actual influence and significance on clinical outcome. The purpose of this randomised clinical trial was to investigate the impact of atmospheric vs. low concentrations of oxygen (O2) during the complete process of human zygote and embryonic development. The study was performed utilising sibling oocytes with the differentiations between the two O2 culture levels measured from fertilisation, from embryo until blastocyst formation, through pregnancy and live birth.
The participants of the study comprised of 258 women who underwent intracytoplasmic sperm injection (ICSI) treatment with a minimum of eight oocytes extracted. The recovered oocytes were cultured and randomly allocated into one of two-treatment groups- incubation in either 5% or 20% O2 conditions. The temperature in both incubators was 37 °C. Evaluation of embryonic development was made in terms of fertilisation, cleavage and the quality of both the embryo and blastocyst. Secondary factors assessed included implantation, maintenance of pregnancy and live births.
A sum of 3,638 matured (metaphase II phase) oocytes were extracted through the study, of which 1833 were incubated under 5% O2 conditions and 1805 sibling oocytes under the alternate 20% O2 treatment condition. Levels of fertilisation and rates of cleavage between the two treatment groups showed no significant differences. However, significant distinctions were seen with the 5% O2 group, which presented significantly more blastomeres (p<0.05), a greater quantity of high quality day 3 embryos (p<0.02) in addition to a significantly increased number of available embryos, per cycle, for transfer and freezing (31.6% vs. 23.1% for the 20% O2 group; P<0.0001). The lower oxygen concentration also seemed to suggest a better influence on clinical outcomes, with significantly higher rates of implantation, pregnancy and live births (22.1% vs. 10.3%, P<0.03; 38.2% vs.18.4%, P<0.05, 34.2% vs. 15.8%, P<0.05 respectively).
Developments in human embryo culturing and cryoconservation techniques in IVF technology have lead to a modification in embryo transfer procedures from early fresh or frozen-thawed cleavage embryo to fresh or frozen-thawed blastocyst stage transfer. The purpose of the clinical trial was to investigate the impact of fresh or frozen-thawed embryo and blastocyst stage transfer upon clinical outcome.
The participants of the study comprised of 1150 women who underwent IVF treatment cycles or intracytoplasmic sperm injection (ICSI) treatment with a total number of 1891 oocytes extracted. The total number of recovered oocytes were experimentally divided into one of two transfer groups- fresh embryonic (n=1150) and frozen-thawed embryonic (n=741) transfers. The 1150 women of the fresh embryonic transfer group were further sub-composed of either cleavage stage (n=799, <35 years old and n=194, >35 years old) or blastocyst stage (n=131, <35 years old and n=26, > 35 years old). The 741 women of the frozen-thawed embryonic transfer group were further sub-composed of either cleavage stage (n=159, <35 years old and n=53, >35 years old) or cleavage stage extended blastocyst culture (n=111, <35 years old and n=26, >35 years old) or blastocyst stage transfer (n=276, <35 years old and n=52, >35 years old). Statistical analysis was then applied to all collected data.
Data on the rates of clinical pregnancy in the fresh cleavage stage embryo and fresh blastocyst transfer in women <35 years were statistically significant (52.7% and 35.88%),(p<0.0001). A statistically significant difference was also noted for the same treatment groups in women >35 years of age (41.24% vs. 26.92%). Rates of clinical pregnancy in the frozen-thawed cleavage stage embryo and frozen-thawed blastocyst transfers were also significant (p<0.0001) in women <35 years (35.29% and 59.8%) and in women >35 years of age (11.32% and 55.8%). Rates of clinical pregnancy between the post thaw cleavage stage extended blastocyst and frozen-thawed blastocyst transfers were also significant (p<0.0001) in women <35 years (47.75% vs. 59.8%) and women >35 years (46.15% vs. 55.8%). The rates of clinical pregnancy differ considerably between the fresh cleavage stage embryo transfers and frozen-thawed cleavage stage embryo transfers in women <35 years of age (52.7% vs. 35.29%) and (41.24% vs. 11.32%) in women >35 years of age. No statistical significant difference was recorded for rates of multiple pregnancy, abortion and ectopic pregnancy between any of the treatment groups. Rates of clinical pregnancy in the frozen-thawed blastocyst transfer group showed the most pleasing clinical outcome among the fresh and frozen embryo transfers.
--Mark Hill These are good summaries of the 2 articles. (5/5)
Lab 2: Uploading a Research Image
Image of a normal human 2-cell embryo with two equal blastomeres (B), a single polar body formation (PB) enclosed by an intact zona pellucida (ZP)
- <pubmed>PMC2898034</pubmed>| 
--Mark Hill This is a relevant image, you have misidentified the species as "human" when this is "mouse", also in the file name. (4/5)
Lab 3: Researching your Project Sub-Heading
- <pubmed> 23723064</pubmed>
--Mark Hill You have included many relevant references related to your project sub-headings. (5/5)
1) Human umbilical cord blood-derived mesencyhmal stem cell transplantation for the treatment of spinal cord injury
The objectives of the study were to investigate the effects of human umbilical cord blood-derived mesencyhmal stem cell (HUCB-MSC) transplantation in the functional repair of spinal cord injury (SCI). The study utilised 46 adult Wistar rats, which were randomly allocated into three treatment groups: Injury (n=15), control (n=15) and transplantation (n=16). Rats in the control group received a physiological saline injection into the site of injury whereas those in the transplantation group received HUCB-MSC suspension into the site of injury. Parameters examined after treatment were behaviour, using the Basso, Beattie, Bresnahan (BBB) locomotor rating scale in weeks one, two and four and histological changes measured through immunohistochemistry (IHC) procedures performed on samples from the rats sacrificed four weeks after subsequent treatment. Analysis of results showed that two weeks following treatment the BBB assessment of the rats in the transplantation group were significantly greater than that of the injury and control groups (P<0.05). Even greater recovery was apparent four weeks following treatment in the transplantation group with the BBB assessment once again, showing statistically significant results (P<0.05) when compared with the other treatment groups. The rats in this group have the ability to stand on their hind limbs and demonstrated coordinated fore and hind limb movements. The expression of Neuron Specific Enolase (NSE) and Glial fibrillary acidic protein (GFAP) in spinal cord tissue was detected via IHC measurements. No levels of these nerve repair factors were detected in the injury or control groups in week four, however a low level of NSE+ cells and a high- level of GFAP+ cells was measured in the transplantation group. The processes of the GFAP+ grew in length and a number of the cells were fibrous and dendritic-cell like, becoming entwined into a neural network within the spinal cord. Therefore the study has shown that following the transplantation of HUCB-MSC’s into the injury site of a rat spinal cord, these implanted cells were able to adapt and differentiate into functioning nerve cells, which was involved in the recovery and regeneration of the damaged spinal cord.
2) Vascular shunts in the fetal circulation
During fetal development the liver and lungs are non-functional, thus a series of shunts exist in the fetal circulation so that these organs are by-passed.
- Shunt 1: Ductus Arteriosus= Connects the pulmonary artery to the proximal descending aorta to shunt most of the blood away from the lungs
- Shunt 2: Ductus Venosus= Shunts a portion of the left umbilical vein blood flow directly to the inferior vena cava
- Shunt 3: Foramen Ovale= Shunts highly oxygenated blood from right atrium to left atrium. Located in atrial septum.
--Mark Hill Very good (5/5)
Bronchopulmonary Dysplasia: CAUSES Bronchopulmonary dysplasia is a chronic lung condition most prevalent among premature infants requiring oxygen and mechanical ventilation. In most cases infants who develop BPD are greater than 10 weeks premature, weigh less than 1kg and often have severe breathing difficulties, often being born with serious respiratory distress syndrome (RDS). The lungs of a premature infant are delicate and normally not fully developed and as a result can be acutely injured by such factors as mechanical ventilation and oxygen therapy, which may cause irritation and inflammation of an infant’s lung. The acute damage may then result in the interference or inhibition of lung alveolar and vascular development. Certain factors can cause irritation or damage to premature infants lungs: (Alan H. Jobe 2001).
- Ventilation machines use pressure to force air into the airway and lungs of newborns with breathing problems or those who cannot breathe on their own. The pressure of the ventilators may however lead to irritation and harm to the babies’ lungs and is therefore only used when crucial
- High levels of oxygen administered though oxygen therapy can inflame the lining of the lungs and injure the airways- may also lead to slow lung development in premature infants
- Infections may lead to inflammation of delicate lung tissue and subsequent narrowing of airways. Troublesome breathing often results which may also increase the need for ventilation and oxygen support measures
- A number of studies demonstrate a possible link between genetics and the acquisition of BPD (NHLBI, 2014).
- What Causes Bronchopulmonary Dysplasia? - NHLBI, 2014. What Causes Bronchopulmonary Dysplasia? - NHLBI, NIH. [ONLINE] Available at: http://www.nhlbi.nih.gov/health/health-topics/topics/bpd/causes.html. [Accessed 10.9.14]
- Alan H. Jobe and Eduardo Bancalari "Bronchopulmonary Dysplasia", American Journal of Respiratory and Critical Care Medicine, Vol. 163, No. 7 (2001), pp. 1723-1729.
--Mark Hill Bronchopulmonary dysplasia is described well, but it is more of a "clinical"effect on lung rather than a truly developmental abnormality. I also want you to use research literature rather than online information sources (3/5)
- Identify and write a brief description of the findings of a recent research paper on development of one of the endocrine organs covered in today's practical:
The pancreas and other gastrointestinal organs are embryologically derived from endodermal origins. The pancreas is developed via the union of two separate buds; the dorsal and the ventral, which appear at the foregut/midgut junction by the fifth week of gestation. The dorsal pancreatic bud forms initially and will produce a segment of the head and uncinate process whole body and tail of the pancreas whereas the ventral bud surfacing alongside the bile duct will form only a small segment of the head and uncinate process. Subsequent expansion and rotation of the duodenum eventually unites both dorsal and ventral buds forming the complete pancreas. The pancreatic duct will form via the fusion of the ventral bud duct and distal part of the dorsal bud duct- this will provide fro the exocrine function. Endocrine function however is provided via the endodermal cell differentiation into islet cells. Whilst the exocrine function of the fetus will initiate postnatally, endocrine function- secretion of insulin, glucagon and somatostatin can be measured from 10 to 15 weeks onwards. The purpose of the study was to investigate the impact of maternal nutrition upon the intrauterine environment, more specifically the key stages of human pancreatic development and factors controlling β-cell development and mass. Little is known about the key molecular pathways and mechanisms that control the adaptive programming of β-cells however it is understood that maternal factors including over nutrition or obesity may affect the ability to maintain fetal β-cell mass resulting in a heightened risk of type 2 diabetes in adulthood.
- Identify the embryonic layers and tissues that contribute to the developing teeth:
Odontoblast: Cells of neural crest origin, that is part of the outer surface of the dental pulp and functions in dentiogenesis.
Ameloblast: Cells derived from oral epithelium tissue of ectodermal origin annd function in the deposition of tooth enamel.
Periodontal ligament: Develops from the dental sac of the tooth germ and function as a type of specialised connective tissue fiber that attaches a tooth to the alveolar bone.
--Mark Hill Good recent article on pancreas and diet effects. Tooth origins are fine (5/5)
Embryonic Development of the Human Ovary:
The chromosomal sex of the human embryo is resolute from the stage of oocyte fertilisation by the type of sperm- either X or Y carrying that fertilises the X-bearing oocyte. The early stages of genital development (<7weeks) in both male and female are similar and thus collectively referred to as the ‘indifferent stage’ of sexual development. The sources of embryonic gonad development are the mesothelium lining the posterior abdominal wall, underlying mesenchyme and primordial germ cells. The earliest phases of gonad development occur within the 5th week of gestation, as there is a thickening of the mesothelium on the medial side of the mesonephros, which is the primitive kidney. Propagation of this epithelium and the underlying mesenchyme will produce the gonadal ridge. By week 6, gonadal cords will then develop and grow into the underlying mesenchyme. The indifferent gonad now comprises an external cortex and internal medulla. The cortex region will now differentiate into an ovary in those embryos with an XX sex chromosome with the medulla region degenerating. Additionally in week 6, there are two pairs of genital ducts that are present- the mesonephric ducts (wolffian ducts) and the paramesonephric ducts (mullerian ducts), which have a leading role in the development of the female reproductive system. The mesonephric ducts of female embryos will degenerate due to the lack of testosterone. The paramesonephric ducts will develop majority of the female genital tract. The uterine tubes will form from the unfused cranial portion of the duct, whereas the caudal portions develop into the uterovaginal primordium, which will produce the uterus and superior part of the vagina. Gonadal development is a gradual process in the female embryo and by week 10 onwards there is further gonad and external genital growth. The cortical cords ranging from the surface epithelium of the maturing ovary into the underlying mesenchyme grow in size and primordial germ cells are integrated into them. By 16 weeks of development the cords will start to breakdown into isolated cell clusters known as primordial follicles. Each primordial follicle will enclose an oogonium, which originated from a primordial germ cell. A single layer of flattened follicular cells, which are derived from the surface epithelium, surrounds the oogonium. Many oogonia will degenerate before birth with approximately 2 million that will remain and grow to become primary oocytes.
<pubmed> 24741072</pubmed> Moore, K.L. & Persuad, T.V.N. (2008). The Developing Human: clinically oriented embryology (8th ed.). Philadelphia: Saunders
Image Reference: Bailey, F.R. and Miller, A.M. (1921). Text-Book of Embryology. New York: William Wood and Co.
--Mark Hill Ovary description is good, but straight from the textbook. Please do not use textbook source. (3/5)
Lab 9: Peer Review of Student Projects
Introduction part is very clear and informative and nicely organised. The images look great, however I think that perhaps some information should be placed alongside them to describe what each figure/image is demonstrating. Maybe a few sentences to describe an overall objective of the page can also be added for extra clarity. Lung development stages section has a great layout and is nice and easy to read. A few images added to the table may improve this section as the visualisation of this developmental process would greatly aid in the readers understanding of the topic. Referencing also needs a little work to be presented correctly. I particularly like the current research section of the page- the presentation of new findings according to different sub-topics in respiratory development is a great idea! The image itself would look better with a different placement as it seems rather isolated and again some information as to what the diagram is demonstrating would be beneficial. The historic findings section was particularly well done also, great images used and referencing is done very well. The abnormalities section was a great read, nicely organised via the subheadings and well written. Some subheadings may need a little more detail with information and maybe a few more images would also go a long way, referencing was done very well. Overall really nice page! ☺
The introduction section of the page is well written and provides a nice overview to the whole project that unifies each subheading of the project as a whole. Some potential ideas for historic findings section may be to use some sort of timeline or table with some visual effects through historical images/ drawings. Developmental timeline is clear and concise however this section would be more effective with a greater amount of detail and perhaps a panel of images to convey visually each stage of development. The current research models section was very well written with two relevant current papers discussed- perhaps a few additional papers can be cited- even under an expanded box format so that the readers can be linked to other current studies in the area of interest. The explanation of the figure is also really well presented and described. The section with the subheadings of kidney, ureter and bladder is very well researched and presented- well informed, great use of images and also well referenced. One area for improvement could perhaps be presenting the information in a simpler way as at times it seems too bunched up- maybe smaller bullet points. The image within the urethra subheading is missing a figure caption. Abnormalities section was very descriptive and informative- may be a few more abnormalities could be listed. Overall reference section is also done correctly although some sections individual references need to be integrated into this overall section.
A nice overview is presented for basic information to be presented onto the project page, with a descriptive introduction into the topic of GIT. Perhaps this section could include a brief mention of the aims of the page and perhaps a few images to make it more visually appealing. Timeline section is particularly extensive, however perhaps the layout can be altered- either adding further information to each developmental stage or even using a table format with images to aid the readers understanding of the processes. The subheadings of this section were also a particularly nice way to structure the information. Recent findings needs a bit more work- perhaps a particular focus could be established for this section of even links to a few articles organised by research into particular organs of the GIT. A few images would also increase the visual appeal to this section. The main body of information (foregut, midgut and hind-gut) are well covered and written- there is evidence of extensive research and work put into this section. The hand drawing idea was also particularly a good idea also with a proper description added to the image. Formatting to this section could be a little more unified however as some section use different styles of bullet points and ways to present the information. Deformities section is greatly informative; perhaps a few more should be presented with accompanying images. The overall references section was formatted correctly.
This page overall looks really fantastic and highly informative! A brief introduction is lacking at the start of the page- would be nice to briefly introduce the topic of the page and the intended goals for the page to achieve to present to the reader. This section would also nicely unify the contents of the project as a whole. The system development part has very extensive information with a great use of formatting styles- with the use of bullet points and the table format. Perhaps the placement of the image and video could be re-integrated into this section as it seems fairly isolated and doesn’t unify this section greatly. Also a brief description could be added to the image and video to describe what is being presented. The video however is a great idea and a good choice of one too! Very informative and simplifies the information being presented. Current research section looks great so far; few changes to formatting would be beneficial (i.e. with font styles and the general structure of bullet points can be made more visually presentable). There is evidence of extensive research however and the use of subheadings also nicely structures this section. There is an error with one of the uploaded images, which should be corrected however. The information presented within the historic findings section seems highly extensive, although perhaps the formatting could be altered to make it look less bulky and easier to read and understand for the reader. The abnormalities section is greatly done, very informative and looks fantastic, well done! All references should be integrated into the final references section that is already been established.
An introduction section should be added to the beginning of this page as it is highly useful to unify the project as a whole and so as to introduce the topics to be discussed to the reader. A basic overview of what particular endocrine organs are to be presented as well as associated abnormalities may need to be mentioned briefly. The individual subheadings focusing on a particular endocrine organ is a nice layout, which is then further, subdivided into the timeline, abnormalities and recent findings sections. This is a well thought out layout and seems to work well however there is a lack of unison between different sections and this chosen layout- perhaps more communication is needed between team members. The structure of the timeline is also particularly well done in these sections and nicely introduces each organs developmental stages. The use of extensive images is also great to see, the brief description of each image/ figure is also highly relevant. Perhaps a few hand drawn images can also be added- as this would be beneficial for student learning as it is simple and easier way to present a process of development. The written information is nicely presented also, there doesn't seem to be too much muddled information, it is concise and informative. Historic findings section doesn't seem to have been completed so perhaps could be integrated into each individual subheading or an overall small section briefly touching on this topic also. So overall I believe the cohesiveness and flow of the project seems to lacking, however there is evidence of extensive research and development of ideas very clearly. The references of each section also need to be unified under a single subheading at the end of the project.
At this stage this project seems to be put together very well. The introduction has a very neat layout and structure, it is well developed and integrates the concepts of the whole page together well. Fetal development section has a fantastic diagram, very relevant and has a great visual appeal and is very helpful form of understanding the concepts being presented. The bullet points are a nice way to break up the page so that it doesn’t appear too clumped, however it may be useful to at times have a little more detail – particularly in the fetal development section. The brain development section has nice formatting with the use of bullet points and then a table. Perhaps at times small paragraphs can also be useful especially when explaining complex processes like the developing brain. The images are well described in this section too. Perhaps another improvement can be the addition of hand drawn images as this is a student page and a simplistic drawing of complex concepts can make things easier to understand for the reader. The current research models section seems to be extensively researched, however shouldn’t be left as it is at them moment- the referencing should be worked on and integrated into the final section of references. Some images may also be of benefit to this section. Abnormalities section is great so far! The final reference section has a good start- although more of the references must be integrated into this section.
A few sentences should be added to your introduction to better introduce what the project page is about and the main objectives or aims. Timeline needs some work, a few ideas could include a bullet point structure or the use of a simple table with images to accompany the overview of musculoskeletal development. The background embryonic development section is particularly useful to giving the project some background information- internal citations are also well presented. Molecular and cellular regulation section could use some images to increase the visual appeal – perhaps from some recent research papers. Tendon development and abnormalities section could also use some more detail and images. Perhaps some hand drawn images would be useful to help describe difficult concepts. References section is well presented and developed- although a few errors need to be fixed with a few references.
--Mark Hill Very good peer feedback (9/10)
Peroxidasin is essential for eye development in the mouse: The precise function of peroxidasin (PXDN) during embryonic eye development is currently inadequately understood. Studies have shown that mutations in PXDN can result in severe abnormalities in the development of the cornea and the lens of the eye. Common manifestations of these abnormalities include congenital corneal opacity, cataract and glaucoma strongly associated with anterior segment dysgenesis (ASD). Recent findings suggest a complex molecular network of regulation in eye development and growth regulated through a complex series of genes and transcription factors. Mutations in the human PXDN gene have been exhibited to cause a severe form of ASD, which involves congenital corneal opacity, cataract and glaucoma- suggesting this gene performs a vital role during the development of the eye. The current study reports the first PXDN mutation in the mouse, which was produced by treatment with ENU (N-ethyl-N-nitrosourea) and produced a recessive phenotypic expression in subsequent offspring. Sequence analysis of cDNA exposed a T3816A mutation, which produced a premature stop codon (Cys1272X) in the peroxidase domain therefore affecting the enzymatic activity of the peroxidase enzyme. A deficiency of PXDN within the mouse mutants produced eye developmental defects associated with ASD and even more severe eye defects including microphthalmia. Besides producing severe abnormalities within the eye, a key finding is that PXDN performs several functions during embryonic eye development influencing cell proliferation and differentiation as well as basement membrane consolidation. Additional affects within the mouse mutant eyes included ocular inflammation, abnormal expression of Pax6 and Foxe3 and early degenerative harm to the retina and optic nerve. Stage E15.5, approximately the middle stage of development for mice was most affected, with all stages preceding this point exhibiting no gross morphological changes. It was found that Pax6, an essential gene in eye development resulted in dynamic expression changes in mutant eyes and was strongly unregulated at stage E15.5, the stage with the most significant pathological changes. A decreased cell proliferation was exhibited in the lens epithelium in comparison to the wild type mice at E14.5- E15.5 as well as a loss of integrity of the lens capsule. Together these outcomes of this study suggest that PXDN is essential for cell propagation and differentiation throughout eye developmental stages and in addition plays an important role in the consolidation of the basement membrane and in the control of ocular inflammation. 
--Mark Hill Good (5/5)
Chemically induced specification of retinal ganglion cells from human embryonic and induced pluripotent stem cells.: In this investigation an innovative, stepwise chemical procedure for the differentiating of human embryonic stem cells (hESC’s) and induced pluripotent stem (IPS) cells into effective retinal ganglion cells (RGS’s) was examined in the context of a potential advancements to the development of RGC replacement therapy. To proficiently induce the differentiation of the acquired stem cells into ganglion cells, a cell culture with a single culture chemical, DAPT- notch inhibitor was utilised. The hESC’s and IPS cells were differentiated into neuroprogenitors known as neural rosettes demonstrating that notch signalling serves a vital function in stem cell differentiation- and potentially a target for future clinical application. The expression of specific neural and RCG biomarkers (BRN3A, BRN3B, ATOH7/Math5, γ-synuclein, Islet-1, and THY-1) were then inspected. The resulting data demonstrates that roughly 30% of the differentiating stem cells were positive for the expression of RGC markers in addition to the neuronal biomarker TUJI. The differentiated RGC’s were able to generate action potentials as well as create impulsive excitatory postsynaptic currents, which signify that mature, functioning RGC’s were produced. This data effectively demonstrates that the culturing of PAX6/RX-positive stem cells within a single chemical (DAPT) can stimulate these cells to undergo differentiation into mature, functional RGCs. 
--Mark Hill Good (5/5)